DE2103814C3 - Graft copolymer - Google Patents

Description

The invention relates to a graft copolymer which is formed by a basic structure A consisting of

a) 85 to 99.8% by weight of acrylic acid ester or methacrylic acid ester units, of which up to /.u 50 wt .-% by units of acrylic acid, Methacrylic acid or its amides or nitriles, vinyl acetate, styrene, α-methylstyrene, vinyl toluene or 3- (2-methacryloxyethyl) -2,2-spirocyclohxyloxazolidine can be replaced, and

b) 0.2 to 15% by weight of allyl methacrylate units and optionally 0.2 to 5% by weight of diethylaminoethyl methacrylate, tert-Butyla.Tiinoäthylmethacrylat-, Aminoethyl vinyl ether or dimethylaminoethyl methacrylate units,

and at least one polymeric graft segment B, consisting of 2-ethylhexyl acrylate, butyl acrylate, 2-ethylhexyl methacrylate and / or lauryl methacrylate units, the graft segment making up 5 to 80 wt. ^r / r of the total graft copolymer.

Lower alkyl methacrylate, in particular methyl methacrylate, is preferred as component (a) of the basic structure (A). The proportion of component (a) is preferably 95 to 99.8% by weight of the basic structure (A).

Although component (a) of the basic structure is generally completely composed of those mentioned Acrylic acid ester and methacrylic acid residue units (especially methyl methacrylate units), can be up to 50 wt .-% (preferably up to / u 20 wt%) of this component from units of above-mentioned monomers exist.

The monomer units (b) of the basic structure (A) contain possible active grafts, ie connection points with the graft segment (cn) (B). The component (h) consists preferably of AIIyI-methacrylate and Diiithylaminnäthylmcthacrylat-

Units.

The proportion of component (b) is preferably 0.2 to 5% by weight, in particular 0.4 to 3% by weight of the total basic structure (A). The proportion ϊ of the optional diethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, aminoethyl vinyl ether or dimethylaminoethyl methacrylate units is preferably 0.2 to 2% by weight.

The basic structure (A) is preferably a mixed polymer of methyl methacrylate, allyl methacrylate and diethylaminoethyl methacrylate units.

The molecular weight of the basic structure (A) should be 10,000 to 450,000.

The (the) graft segment (s) (S) of the invention

r, if the graft copolymer is set (sit)

preferably composed of 2-ethylhexyl acrylate and / or butyl acrylate units. Particularly ¹ - preferred are graft segments that consist entirely of 2-

Compose ethylhexyl acrylate units or

.'ο the 2-ethylhexyl acrylate / bulyl acrylate mixed polymer represent.

The number average molecular weight of the

Graft segment (s) is generally 2000 to

50000. The proportion of the graft segment (s) is

j, preferably 10 to 50 wt .-%, in particular 10 to 25% by weight of the total copolymer.

The graft segment (B) is always the branch segment and does not contain any noteworthy proportion of components with active graft sites, as they were designated above u) with (b).

The graft copolymers according to the invention can be prepared by first generating the basic structure (A). This is done by conventional copolymerization of the monomers from which components (a) and (b) are built up.

Suitable amounts of suitable monomers are mixed in an organic liquid in which the the basic structure obtained is soluble, for example in a ketone, ester or aromatic hydrocarbon, together with 0.1 to 2% by weight of a radical polymerization initiator such as benzoyl peroxide or azo-bis-isobutyronitrile. The resulting mixture is then brought to the reaction temperature heated and held at that temperature until 75 to 95% conversion has occurred (determined by measuring the amount of unreacted monomers present). Then there a suitable merge of graftable monomers or graftable monomers is added to the mixture and 0.1 to 2% of a graft initiator such as tcrt.-butylpcroxypivalate or tert-butylpcracetate. The mixture is then heated to reflux temperature and held at this temperature until the degree of conversion to the graft copolymer is more than 90%. The resulting graft copolymer can be extracted from the reaction mass by spray drying to be isolated.

The production of the graft copolymers typically leads to a mixture of polymer molecules with a different number of grafted segments per molecule. The average number of grafted segments (B) per basic structure (A) is generally from 0.5 to 5, preferably from 1 to 2.

The molecular weight of the total graft mixture should be 15,000 to 500,000.

If you use the graft copolymers of the invention

If dispersed or dissolved in a suitable organic liquid, one obtains paints that are used as automotive paints, can be used for devices and the like. Films obtained from the graft copolymers have a high level of impact resistance, which makes them suitable for painting furniture. Examples Organic liquids that can be used to produce such paints are aromatic and aliphatic hydrocarbons, esters, ketones, such as acetone or methyl ethyl ketone, alcohols, such as ethanol or isopropanol, as well as their mixtures. Before use, the mixtures can be diluted to the viscosity of use with common paint solvents.

Before dilution, the mixtures generally have a solids content of K) to 60% by weight of the total mixture.

Although the dispersions or solutions of the graft copolymers are used as such It is generally desirable to use pigments and plasticizers in the usual manner and in to be added in the usual quantities.

The coating compositions are applied by dipping, brushing or spraying. The coating films are air dried or 10 to 60 minutes Baked in at temperatures up to 350 ° C and surrendered clear, durable top coats.

The following examples illustrate the invention. All parts are parts by weight. The abbreviations have following meanings:

MMA methyl methacrylate

DÄAM diethylaminoethyl methacrylate

AMA allyl methacrylate

2-ÄHA 2-ethylhexyl acrylate

BA butyl acrylate.

example 1

304.9 parts of MMA, 3.2 parts of DÄAM, 3.6 parts of AMA, 48.4 parts of butyl acetate and 75.3 parts of ethyl acetate are mixed and heated to reflux temperature. Then a mixture of 1.4 is used Parts of azo-bis-isobutyronitrile and 15.4 parts of ethyl acetate and holds the reaction mass for 10 min. at the reflux temperature. Then you move the reaction mass for 80 min. With a mixture of 0.43 parts of azo-bis-isobutyronitrile, 165.0 Parts of ethyl acetate and 32.3 parts of ethyl acetate. then a mixture of 21.5 parts of 2-ÄHA, 0.21 Parts of azo-bis-isobutyronitrile and 17.9 parts of an aliphatic hydrocarbon are added, the heated Rcaktionsmassc up to the reflux temperature and holds it for 10 minutes at this temperature.

A mixture of 35.9 parts of 2-ÄHA and 0.36 parts of tert-butyl peroxyphoid is then added for 30 minutes to. A mixture of 35.9 parts of MMA and 0.43 parts of tert-butyl peroxypivalate is then added for 45 minutes and 0.86 parts of azo bis isobutyronitrile added.

Next, there are 86.1 parts of an aliphatic hydrocarbon and 0.21 part of tertiary butyl peroxypivalate mixed and the reaction mass over a

ι »period of 30 minutes added. Then you let him Stand for 30 minutes.

The reaction is terminated by adding 150.7 parts to the reaction mass for 20 minutes aliphatic hydrocarbons added and

i'i then cools the reaction mass. You get a dispersion of a graft copolymer from an MMA / AMA / DÄAM basic structure and a Poly (2ÄHA) graft segment with a solids content of 38.6%. The graft copolymer can

> n can be isolated by spray drying.

Example 2

The procedure is as in Example 1 with the exception that 14.4 parts of 2-ÄHA and r. 21.5 parts BA instead of 21.5 parts 2-ÄHA added.

The reaction results in a graft copolymer

with a MMA / AMA / DÄAM basic structure and

a graft segment made of 2-ÄHA and BA. The dis-

i (i persion has a solids content of 35.3%.

Example 3

A pigment paste is prepared by adding 24.4 parts of the organosol from Example 1 to 14.1 parts

ii of a solvent mixture of about 45.5 parts of naphthenes, 47.9 parts of paraffins, 7.8 parts of aromatics and 0.01 part of sulfur, 14.05 parts of xylene and 58.0 parts of TiO ₂ . The paste obtained is ground with sand.

in 110.55 parts of the above pigment paste are added with stirring 186.52 parts of the organosol from example 1.18 parts of bis (methylcyclohexyl) phthalate as a plasticizer, 17.9 parts of xylene and 18.03 parts of the aforementioned solvent mixture.

4 ". A white, pigmented varnish is obtained is diluted for spraying by adding 80 parts of ethylene glycol monobutyl ether acetate, 49 parts of xylene and 49 parts of the aforementioned solvent mixture to 222 parts of the white lacquer gives.

The mixture obtained is sprayed on and baked for 30 minutes at 162.78 ° C, a durable, receives white top coat.

Claims (1)

Claim: Graft copolymer, characterized by a basic structure A, consisting of a) from 85 to 99.8 weight .-% acrylic acid ester or methacrylic acid ester units, of which up to 50 wt .-% of units of acrylic acid, methacrylic acid or their amides or nitriles, vinyl acetate, styrene, a- methylstyrene, vinyltoluene or 3 - (2-Methacryloxyäthyl) - 2,2-spirocyclohexyloxazolidine can be replaced, and b) 0.2 to 15% by weight of alkyl methacrylate units and optionally 0.2 to 5% by weight of diethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, Aminoethyl vinyl ether or dimethylaminoethyl methacrylate units, and at least one polymeric graft segment B, consisting of 2-ethylhexyl acrylate and / or butyl acrylate units or 2-ethylhexyl methacrylate or lauryl methacrylate units, the graft segment making up 5 to 80% by weight of the total graft copolymer.